Bacterial Toxins- Lecture 10/7/21 Flashcards
4 Steps for bacterial disease
- Encounter host
- Establish an infectious niche
- Multiply, cause tissue damage
- Spread to other tissues, hosts, or both
Toxin
A protein that damages eukaryotic cells
Endotoxins
Non-proteinaceous lipopolysaccharide of gram-negative bacteria, overreaction of host immune response
C. Difficile toxin structure (4 domains)
- Enzymatically active domain
- Cysteine protease domain (auto cleaves)
- Hydrophibic region
- Receptor binding carbohydrates
Mechanism of C. Difficile
Threads through once early endosome acidifies-> acts on Rho proteins (G protein) which causes cell death
Botulism symptom
Clostridium Botulinum causes flaccid paralysis
Botulism mechanism of action
Cleaves proteins involved in the real ease of Acetylcholine at synaptic cleft, can’t contract muscles
A-B toxin
A unit is enzymatically active
B unit is cell binding, triggers RME
Tetanus symptoms
Clostridium tentani causes spastic paralysis
Tetanus mechanism of action
Same as botulism, but targets GABA in the CNS which causes overactive contraction
Cholera symptoms
A lot of diarrhea
Cholera mechanism of action
Secretes AB toxin that locks GI G protein in on position, decreasing Na+ absorption and increases Cl- secretion, leading to mass water secretion